docs: def numerical_components(self):
          """
          :return: lambda functions of each of the analytical components in
              model_dict, to be used in numerical calculation.
          """
          Ans = variabletuple('Ans', self.keys())
          # All components must feature the independent vars and params, that's
          # the API convention. But for those components which also contain
          # interdependence, we add those vars
          components = []
          for var, expr in self.items():
              dependencies = self.connectivity_mapping[var]
              # vars first, then params, and alphabetically within each group
              key = lambda arg: [isinstance(arg, Parameter), str(arg)]
              ordered = sorted(dependencies, key=key)
              components.append(sympy_to_py(expr, ordered))
          return Ans(*components)